A known seat device, for example described in JPH08 (1997)-058453, includes a rolling mechanism for inclining the seat in accordance with the centrifugal force in the lateral direction applied to the vehicle. With the construction described in JPH08 (1997)-058453, the rolling mechanism is positioned under a seat cushion, such that the seat rotates relative to a rotational center in approximately central back and forth direction of the seat. Accordingly, for example, in case the right side of the seat is moved downward, the left side of the seat is moved upward to incline the seat.
In case the seat device includes the rolling mechanism and a height adjusting function for adjusting the height of the seat relative to a vehicle floor depending on a driving posture of the occupant, it is required to position the height adjusting device either over or under the rolling mechanism. However, it is difficult to provide plural mechanisms under the seat relative to the vehicle floor due to the limitation of the space.
A need thus exists for a seat device for vehicle including a rolling function and a height adjusting function for a seat, which are positioned between the seat and a vehicle floor.